Sökning: "collimation"

Visar resultat 1 - 5 av 11 avhandlingar innehållade ordet collimation.

  1. 1. SPECT Imaging using Pinhole Collimation : System Design and Simulation Studies for Pre-Clinical and Clinical Imaging

    Författare :Mikael Peterson; Lund Medicinsk strålningsfysik; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Pinhole SPECT tomography; Nuclear medicine imaging; Monte Carlo-based image reconstruction;

    Sammanfattning : The focus of this dissertation is the use of pinhole collimation in Nuclear Medicine. A pinhole is a single aperture in an opaque material that is placed between the detector and source of interest, and photons must pass through the hole to reach the detector. The choices of pinhole parameters, e.g. LÄS MER

  2. 2. Development of a compact high energy treatment unit combining narrow pencil beam scanning and multileaf collimation

    Författare :Roger Svensson; Stockholms universitet; []

    Sammanfattning : .... LÄS MER

  3. 3. Spectral Mammography with X-Ray Optics and a Photon-Counting Detector

    Författare :Erik Fredenberg; Mats Danielsson; Björn Cederström; Jeffrey H. Siewerdsen; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; NATURVETENSKAP; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; MEDICIN OCH HÄLSOVETENSKAP; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; MEDICAL AND HEALTH SCIENCES; mammography; x-ray optics; photon counting; spectral shaping; spectral imaging; collimation; radiation dose; signal-to-noise ratio; quantum noise; anatomical noise; spatial resolution; x-ray flux; ; TECHNOLOGY; TEKNIKVETENSKAP; Engineering physics; Teknisk fysik; Optical physics; Optisk fysik; Other engineering physics; Övrig teknisk fysik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik; Medical engineering; Medicinsk teknik; Radiological research; Radiologisk forskning;

    Sammanfattning : Early detection is vital to successfully treating breast cancer, and mammography screening is the most efficient and wide-spread method to reach this goal. Imaging low-contrast targets, while minimizing the radiation exposure to a large population is, however, a major challenge. LÄS MER

  4. 4. Diagnostic criteria and dose limiting approaches for image modalities in odontology

    Författare :Daniel Benchimol; Karolinska Institutet; Karolinska Institutet; []

    Sammanfattning : Objectives: Technical innovations in radiography enable the development of new approaches to reduce the dose to patients. The aim of this thesis was to explore dose optimization approaches for the most frequently used radiographic modalities in dentistry. Material and Methods. LÄS MER

  5. 5. Linear and Nonlinear Transport in Quantum Nanostructures

    Författare :Anneli Löfgren; Fasta tillståndets fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; magnetoconductance; mesoscopic; electron billiard; quantum dot; quantum ratchets; non-linear; symmetries; non-symmetric conduction; rectification; artificial material; Halvledarfysik; Fysicumarkivet A:2002:Löfgren; ballistic transport; quantum transport; 2DEG; Semiconductory physics; InP InGaAs; GaAs AlGaAs;

    Sammanfattning : In this thesis, electron transport in mesoscopic semiconductor nanostructures, in particular so-called electron billiards or quantum dots, is studied. The thesis can be divided into two areas: the linear response regime of transport, and the nonlinear response regime of transport. LÄS MER